1. Technical Field
This invention relates generally to medical methods and apparatus and more specifically to procedures for forming a channel through a stomach wall in percutaneous gastrostomy.
2. Background Art
In recent years, the field of percutaneous gastrostomy has emerged in veterinary medicine as an effective technique for providing nutritional support for critically ill small animals. Animals that are malnourished or unwilling or unable to eat may benefit from this treatment, especially if nutritional support is needed for longer than about one week.
Percutaneous gastrostomy is a procedure involving the placement of a feeding tube through the skin, abdomen wall, and stomach wall of a patient as a means of supplying nutrients to the stomach without involving the head or esophagus. Percutaneous placement of the gastrostomy tube can be faster and involve less tissue trauma than the alternative of surgical placement, which involves making a grid incision through the skin and abdominal wall to locate and reach the stomach wall.
Percutaneous gastrostomy has been done in the past with the aid of an endoscope, which is a fiber-optic instrument that can be directed through the esophagus and into the stomach for viewing the inside of the stomach. The endoscope typically has a forceps extending through it and reaching to the distal end and a channel for delivery of gas or liquid to the vicinity of the distal end.
Percutaneous Endoscopic Gastrostomy (PEG) for veterinary patients is discussed in the article "Enteral Feeding of Critically Ill Pets: The Choices and Techniques," by P. Jane Armstrong, Veterinary Medicine, September 1992. Typically, the endoscope is introduced into the stomach and air is pumped through the endoscope to insufflate and distend the stomach. As the endoscopist views the inside of the stomach wall, an assistant chooses a point on the abdominal wall where the endoscope light can be clearly seen through the abdominal wall. The location of that point is confirmed by the assistant applying pressure to the abdominal wall and the endoscopist observing the resulting depression in the stomach wall. After good visualization of this point is confirmed, the assistant inserts a needle holding a suture strand through the skin, the abdominal wall, and stomach wall, creating a channel through these tissues. The endoscopist uses the endoscope forceps to grasp the strand and pulls the endoscope out of the stomach and esophagus and thus pulls the suture strand out through the patient's mouth.
The end of the suture strand exiting the mouth is attached to a pipette tip and then to a feeding tube such as a mushroom-shaped catheter. The pipette tip is usually threaded tip end first on to the suture strand to act as a smooth guide for the end of the feeding tube as it travels through the esophagus.
The end of the suture strand exiting the abdominal wall is pulled so that the pipette and feeding tube move through the esophagus, into the stomach, and into the channel through the stomach wall and abdominal wall. The suture strand and pipette may then be removed from the end of the feeding tube which exits from the abdominal skin. The feeding tube may be held in place by flanges, tape, or other anchoring devices. The feeding tube then serves as a conduit for nutritional supplements to flow into the stomach.
Thus, PEG involves locating the site for the channel by viewing the inside of the stomach and involves piercing into the abdominal wall and stomach wall from the outside of the body. PEG requires two people to perform the technique and requires an expensive endoscopic instrument.
Similar PEG techniques are used in human gastrostomy operations. Grobe (U.S. Pat. No. 5,112,310) discusses the "pull" PEG technique, which is similar to the veterinary technique described above. Grobe also discusses the similar "push" and "introducer" techniques and discloses apparatus for use in PEG. All these techniques involve the viewing of the inside of the stomach with an endoscope and an incision made from the outside toward the inside of the body and stomach.
Several U.S. patents disclose apparatus for use in PEG. Krol (U.S. Pat. No. 4,573,576) discloses a PEG kit. Picha et al. (U.S. Pat. No. 5,007,900) discloses a T-bar device for anchoring a catheter in the abdomen wall. Poirier et al. (U.S. Pat. No. 4,897,081) discloses a button-like device for anchoring a catheter.
Improved methods and devices, which are simple, reliable, and safe, are needed for placement of a percutaneous gastrostomy tube. Methods that can be done by one person are needed. Apparatus that is simpler and less expensive than an endoscope is needed.